The communication speed increases in the Long Term Evolution (LTE), which is a next generation mobile communication, compared with the third generation mobile communication. The increase in communication speed is realized by an increased radio bandwidth, which is used between a mobile communication device and a radio base station. It is thus necessary to increase a line speed or a line capacity of a backhaul line connecting a higher-level network, which includes the mobility management element (MME) and the serving gate way (S-GW), with the radio base station. However, an amount of data transmitted from the mobile communication device to the radio base station may exceed an amount of data which can be transmitted on the backhaul line depending on a quality of a network or the backhaul line built based on a network design of a telecommunications carrier. In this case, the radio base station carries out flow control to limit the amount of data transmitted to the backhaul line.
Japanese Unexamined Patent Application Publication (JP-A) No. 2006-197605 (hereinafter, referred to as Patent Literature 1) describes a technology for efficiently transmitting a control traffic and a bearer traffic on a backhaul line. In general, a resource on the backhaul line is sufficiently allocated to the control traffic requiring a high reliability. Therefore, a bandwidth available for transmitting the bearer traffic is reduced. To address this problem, Patent Literature 1 discloses a communication method involving monitoring the control traffic transmitted on the backhaul line, and allocating a proper amount of the resource to the control traffic transmitted on the backhaul line.
Japanese Unexamined Patent Application Publication (JP-A) No. 2007-336488 (hereinafter, referred to as Patent Literature 2) discloses a method involving allocating a resource to be allocated to channel quality information transmitted from a mobile station to a base station. If an amount of data to be transmitted from the mobile station to the base station is large, the resource to be allocated to the channel quality information is reduced. Moreover, if the amount of data to be transmitted from the mobile station to the base station is small, the resource to be allocated to the channel quality information is increased. As a result, if the amount of data other than control information is large, the resource allocated to the channel quality information corresponding to the control information can be reduced, and hence a large amount of data can be transmitted.
Japanese Unexamined Patent Application Publication (JP-A) No. 2009-111498 (hereinafter, referred to as Patent Literature 3) discloses a control method of receiving a new call from a radio terminal in a radio base station. If a throughput of an existing call, to which a priority lower than a priority set to a new call is set, is lower than a threshold, the radio base station rejects a reception of the new call. As a result, it is possible to prevent a decrease in throughput of an existing call of low priority.